WASHINGTON — House Speaker Paul Ryan declined Wednesday to say the evolving Republican tax cut plan won’t add to already mammoth budget deficits. A chief goal of the effort will be to spark national economic growth, he said in an AP Newsmaker interview.

Ryan, R-Wis., said the GOP’s goal is to enact tax overhaul into law by the end of this year, not simply push it through the heavily Republican House, “so that we start 2018 in a new tax system.”

Rewriting the federal tax code, including lowering rates for corporate and personal income taxes, is a chief goal of President Donald Trump and congressional Republicans. So far it has been a struggle, with differences emerging within the party over how low they can push tax rates and which deductions would have to be eased or eliminated.

Despite talks with Democrats, opposition by virtually all of them seems likely, meaning GOP lawmakers will have to be united.

On another major topic, Ryan said that immigration legislation Congress will be working on “will have to include security measures.”

During his presidential campaign and since, Trump has repeatedly promised to build a wall along the U.S.-Mexico border. Ryan said a physical wall doesn’t need to be constructed along the entire boundary, citing “circumstances on the ground that dictate how we do border security.”

Ryan said Trump took the right approach to phasing out a program that helped young immigrants brought to the country as children and now here illegally.

He said he wanted the White House to allow Congress time to address the issue because he didn’t want it “to be rescinded on day one and create chaos.” He said the six months that Trump has given lawmakers for action is enough time as the program winds down.

Trump has announced he will dismantle the Deferred Action for Childhood Arrivals program in six months. DACA has extended temporary work permits and deportation protection to nearly 800,000 younger immigrants brought to the U.S. as minors.

Ryan said that removing the immigrants covered by the program is “not in our nation’s interest.”